Die for forming metal staying-strips.



W. D. STAN GER.

DIE FOR FORMING METAL STAYING STRIPS.

APPLICATION FILED MAB.11;,1 912.

1,044,283, Patented Nov. 12,1912.

MIA 55555: Wyn/r01? M FZJ- e' 71 712%,,

147 TOR/YE X WILLIAM D. STANGER, OF MERCHANTVILLE, NEW JERSEY.

DIE FOR FORMING METAL STAYING-STRIPS.

Specification of Letters Patent.

Patented Nov. 12, 1912.

Application filed March 14, 1912. Serial N 0. 688,846.

To all whom it may concern:

Be it known that I, VILLIAM D.

STANGER, a citizen of the United States,

residing at Merchantville, county of Camden, and State of New Jersey, have invented a new and useful Improvement in Dies for Forming Metal Staying-Strips, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification. The object of my invention is to produce an improved punch or die for the manufacture of a certain type of metallic strips such as are employed for staying box corners, and for other purposes. The type of strip which I desire 'to roduce is that old and well known type, illustrated, for example in Design Patent No. 25,580 of June 2d, 1896, in which eyelets are formed integral with the strip by punching out therefrom sets of burs, prongs, or pointed projections, each set of pro ections surroundin an orifice and adapted to be pressed into the material of the box or other article and clenched. Heretofore the manufacture of strips containing eyelets of this character has been effected by means of two dies, one having a series of holes and the other a corresponding series of punches, both the holes and punches being circular in cross. section, and each punch being provided with a pyramidal shaped end formlng a series of cutting edges between which edges the punch is either fiat or concaved. With such punching mechanism, it has been -ound practically impossible to form the piojec tions with any close approximation to accuracy or uniformity, inasmuch as the edges of'the projections frequently tear nearthe base thereof in such' manner as to form an undercut, thereby materially weakening the proved die; Fig. 3 is an die of a circular form and in making the punches of the other die of polygonal form in CI'OSSYSGCUOII, the points of the project10ns belng preferably of pyramidal form as heretofore and with straight sides between the cutting edges. Another advantage secured by this form of punch is that the pro ectlons will be bent out from the strip at substantially right-angles thereto instead of curling backward as heretofore, thereby facilitating their insertion into the material of which the box or other article is made.

My invention will be more clearly understood by reference to the accompanying drawings, in which- Figure 1 is a perspective view of a part of a metal strlp with eyelets of the character produced by my invention; Fig. 2 is a perspectlve view of the two members of my imenlarged vertical scctlonal vlew through one of the punches and its corresponding hole; Fig. 4 is a plan View of one of the punches. a is a part of one die, the same containing the holes I), which are circular in cross-section and of substantially the diameter of the eyelets to be formed.

a is a part of the other die, the same carrymg the punches d, which, as shown, are square in cross section, drepresenting the four sides and f the four corners or cuttingr bs. The distance from one corner to the dlametrically opposite corner of a punch is approximately equal to the diameter of its corresponding hole, so that when the punch I'ECIPI'OCBIQSIII the corresponding hole, the corners of the punch will nearly or quite touch the wall of the hole. Each punch is tapered at the end to form four cutting ribs 9 connected by the four flat triangular faces h.

In Fig.- 1 is illustrated a strip provided with the eyelets formed by the cooperation of the punches and holes aforesaid.

While I have illustrated a punch with four flat sides it will be understood that the number of sides depends upon the number of projections that it is desired to form in the eyelet, the only requirement being that the punch shall be provided in its body por tion, withflat sides as distinguished from a production of a strip free from the objections hereinbefore enumerated.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. In mechanism for forming eyelets in metal strips, the combination with a die having a series of'round holes, of a complementary die .forming a corresponding series of punches, each of which has a tapered end and a body which is polygonal in cross section. v

2. In mechanism for forming eyelets in metal strips, the combination with a die having a series of round holes, of a complementary die having a corresponding series of punches, each of which has a body provided with cutting edges and a pyramidal end provided with cutting edges constituting a continuation of the cutting edges of the body, the entire periphery of the body of the punch comprising a series of fiat faces connecting the cutting edges.

3. In mechanism for forming eyelets in metal strips, the combination with a die having a series of round holes, of a complementary die having a corresponding series of punches, each of which has a body which in cross-section is of regular polygonal shape forming longitudinal equi-spaced cutting ribs and a pyramidal end having cutting edges alining with the cutting ribs of the body and tapered to a point.

In testimony of which invention, I have hereunto set my hand, at Philadelphia, on this 12th day of March, 1912.

. WILLIAM D. STANGER.

Witnesses:

M. M. HAMILTON, E. E. WALL. 

